The present invention relates to a new and distinct cultivar of chrysanthemum plant, botanically known as Chrysanthemum×morifolium Ramat., commercially known as a garden mum, and hereinafter referred to by the cultivar denomination ‘Zanmustone’. ‘Zanmustone’ is a product of a breeding and selection program for outdoor pot mums (garden mums) which had the objective of creating new cultivars with a double type inflorescence, a natural season flowering date around August 17 (week 34), blooming for a period of 5 weeks. ‘Zanmustone’ is a seedling resulting from a cross of the female parent id 21570 with an unknown male parent. Plants of the new cultivar ‘Zanmustone’ differ from plants of the female parent in the natural season flowering date. The plants of the female parent flower at the end of September, while those of the seedling flower in mid-August.
The new and distinct cultivar was discovered and selected as a flowering plant by Wilhelmus Bernardus Blom on a cultivated field in Rijsenhout, The Netherlands in 2005. The first act of asexual production of ‘Zanmustone’ was accomplished when vegetative cuttings from the initial selection in 2005 were propagated further in a controlled environment in Rijsenhout, The Netherlands. The new cultivar has been found to retain its distinctive characteristics through successive propagations.